Final answer:
The case that allowed police to systematically stop drivers for informational purposes is Illinois v. Lidster.
Step-by-step explanation:
The case that ruled police can systematically stop drivers in order to seek information is Illinois v. Lidster. Major precedent for police conduct during traffic stops was established in the case of Michigan Department of State Police v. Sitz, where the Supreme Court ruled that sobriety checkpoints did not violate the Fourth Amendment. However, Illinois v. Lidster specifically addressed the ability of police to stop motorists briefly for informational purposes unrelated to the specific drivers being stopped.
it was determined that police may stop a person if they have a reasonable suspicion that the person has committed or is about to commit a crime, and they may frisk the suspect for weapons if they have a reasonable suspicion that the suspect is armed and dangerous without violating the Fourth Amendment.